How to update MediaWiki
Put wiki into readonly mode by editing the LocalSettings.php file and adding the line:
$wgReadOnly = 'Wiki is currently undergoing maintenance, as a result it is in read only mode for a while';
Backup the SQL database, e.g. mysqldump -h host -u wiki -p wiki > wiki.sql
Backup the entire wiki folder:
mkdir backups/20170218 cp -rp http/* backups/20170218/.
Download latest version of MediaWiki from www.mediawiki.org/wiki/Download e.g.
wget https://releases.wikimedia.org/mediawiki/1.28/mediawiki-1.28.2.tar.gz
Unpack the file over the existing installation:
tar zxvf mediawiki-1.28.2.tar.gz -C http/w --strip-components=1
Now run the update:
cd http/w/maintenance php update.php
Don’t forget to take it out of readonly mode by removing or commenting out the $wgReadOnly line in LocalSettings.php